FIG. 8 is a schematic configuration diagram of a conventional fuel cell system. As shown in FIG. 8, means for supplying a hydrogen-containing gas necessary in an electric power generating operation in a conventional fuel cell system 700 is not normally developed as an infrastructure. Therefore, a hydrogen generating device for generating the hydrogen-containing gas necessary in the electric power generating operation is provided.
The hydrogen generating device includes a hydrogen generator 2 including a reformer 3. By the progress of a reforming reaction in a reforming catalyst in the reformer 3, the hydrogen-containing gas is generated from steam and a raw material containing an organic compound containing at least carbon and hydrogen as constituent elements. At this time, the reforming catalyst included in the reformer 3 is heated by a combustor 5 provided adjacent to the reformer 3 to a temperature suitable for the progress of the reforming reaction. In the conventional fuel cell system 700, even if the hydrogen generating device starts generating the hydrogen-containing gas at the time of start-up, it does not supply the hydrogen-containing gas to a fuel cell 1 until the warm-up of the hydrogen generator 2 including the reformer 3 is completed and the composition of the hydrogen-containing gas stabilizes. During this time, a first on-off valve 7a is closed, and a second on-off valve 6 is opened. The hydrogen-containing gas discharged from the hydrogen generator 2 is supplied to the combustor 5 through a second channel 8 that is a bypass channel, and the combustor 5 uses the hydrogen-containing gas as a combustion fuel in a combustion operation (see PTL 1, for example).